This is a good look at the stuff we were constantly warned not to walk on --
cryptobiotic soil crust.

I had thought that the "crypto" had a similar meaning to "cryptic", but it has to do with the
ability to tolerate drying out.

Here's a Wikipedia definition of "cryptobiosis" from http://en.wikipedia.org/wiki/Cryptobiosis:
Cryptobiosis is an ametabolic state of life entered by an organism in response to adverse
environmental conditions such as desiccation, freezing, and oxygen deficiency. In the
cryptobiotic state, all metabolic procedures stop, preventing reproduction, development,
and repair. An organism in a cryptobiotic state can essentially live indefinitely until
environmental conditions return to being hospitable. When this occurs, the organism will
return to its metabolic state of life as it was prior to the cryptobiosis.

And below I quote from an excellent description of the cryptobiotic soil crust, which is
primarily composed of cyanobacteria -- which we used to call blue-green algae. (Go to this
website address -- http://eduscapes.com/nature/cryptsoil/index1.htm -- for the full article.)

Cyanobacteria occur as single cells or in filament groups. The most common form in the
Colorado Plateau soils are the filamentous type. The filaments are usually surrounded by
sticky mucilaginous sheaths. When rare moisture is received, the cyanobacteria become active,
swelling in size, and expanding through the soil leaving a trail of sticky material along the way.
This binding sheath material forms an intricate fiber web through the soil. Loose particles of
soil are bound together and an unstable land surface becomes very resistant to water and wind
erosion. This binding of the soil surface does not depend on living filaments. Over long periods
of time, layers of abandoned cyanobacteria sheaths can still cling tenaciously to soil and rocks,
providing stability in sandy soils.